This invention relates generally to evaporation refrigerators, and more particularly to a continuously operating, .sup.3 He evaporation refrigerator well adapted to providing subkelvin temperatures in space flight environments.
There is need for the above type refrigerators for scientific experiments and apparatus that require very low temperatures, i.e. down to about 0.3K. In such a .sup.3 He evaporation refrigerator, the evaporator is the coldest part of the system during normal operation, and that is where heat is absorbed from an attached load or device that is to be cooled. During steady state operation where the temperature of the evaporator remains constant, the sum of the heat absorbed from the load and the parasitic heat leaking into the evaporator per second is just equal to the latent heat of atoms evaporated from the liquid there per second.
Localization of the liquid and vapor in selected regions and establishment and control of the interfaces between the liquid and vapor phases in the condenser-collector and in the evaporator are of prime importance. In a conventional evaporation refrigerator that operates in terrestrial laboratories, this is accomplished simply by gravity holding the liquid at the bottom of the condenser-collector and evaporator chambers. In the reduced gravity of space, the two phases will not be positioned in such a simple way in the absence of applied forces.